Conserving Critical Habitats in the Conservation Crescent - The Stony Island Story

Mary Ginnebaugh, Grosse Ile Nature and Land Conservancy

Introduction and History

The Detroit River has been designated by state, provincial and federal governments of Canada and U.S. as an international Area of Concern. This "distinction" was made because of the river's recognized environmental problems and ecological impairments stemming from urban growth and industrial development. Since the late 1800s, it has been well documented that over 95% of the Detroit River's original wetland habitat has been lost through urban and industrial development. Many areas of the Detroit River and Trenton Channel have sediments contaminated with high concentrations of metals and organic compounds which are a legacy of industrial practices and a naive understanding of the ecosystem.

Although the historical impacts have played a significant part in the river's environmental problems, there continues to be environmental degradation. Municipal and industrial discharges, poor land use practices, combined sewer overflows, urban and agricultural runoff and contaminants from air deposition continue. To address these environmental problems and improve the overall quality of the Detroit River ecosystem, binational efforts have been made to develop and implement a meaningful Remedial Action Plan. A high priority for action is the identification and protection of the remaining fish and wildlife habitat in the Detroit River watershed.

Much of the existing, high quality habitat can be found in the lower reaches, near the mouth of the Detroit River. The "Conservation Crescent" has been identified as the area that surrounds the southern portion of Grosse Ile and includes the smaller islands and shoreline areas along the Canadian and U.S. sides of the river. Stony Island anchors the northeast portion of the crescent and Humbug Marsh anchors the northwest portion.

Stony Island was originally Potawatomie Indian territory used for hunting and fishing. After being deeded to the Macombs of Grosse Ile in 1781, it became part of a railroad-ferry river crossing between Canada and the U.S. for the Canadian Southern Railroad during the late 1800s. During the 1930s, the island was used as a center of operations to create the Livingston Channel, and then later as a base for dredging the shipping channel. A small residential community existed on the island during this time. These homes no longer exist, however, abandoned machine shops and several sunken non-motorized barges remain. The Island is currently a part of Grosse Ile Township and is a residentially zoned area. No utilities are available, however.

As a direct response to the continued pressures on Grosse Ile for development and a constant threat of permanently losing natural areas on the island, the Grosse Ile Nature and Land Conservancy was formed. The mission of the organization is to acquire natural areas on Grosse Ile through purchase, conservation easements and donations, for the purpose of preservation, protection and public benefit. The Conservancy recognized the ecological benefit of Stony Island in the lower Detroit River, and pursued acquisition of the island in 1994 for the purpose of habitat protection and conservation.


The Stony Island area is a mix of upland, wetland and swift-moving, shallow water, and is one of the largest remaining wildlife habitat and fish spawning areas in the lower Detroit River. The Island is roughly 40.5 ha (100 acres) and is protected by a limestone armoured barrier that encloses a large shallow bay area used extensively by waterfowl for staging during migration. Over 23 species of migrating waterfowl have been identified here (Manny et al. 1988). There are approximately 20.2 ha (50 acres) of upland area which includes a mix of vegetation; massive chinkapin oak, hackberry and cottonwood are among the old growth. The hard bottom shoal of limestone provides spawning for 65 species fish, including perch and walleye (Manny et al. 1988). The surrounding macrophyte beds also provide habitat for a variety of fish.


The ability to secure the $750,000 (U.S.) to purchase Stony Island did not come without a tremendous amount of persistence and effort by members of the Conservancy, support from federal and state agencies and important contacts made by Township officials. Stony Island nominated for public land acquisition through the Natural Resources Trust Fund Board in 1995 and again in 1996. After a special meeting between Grosse Ile Township officials and Michigan's Governor Engler, Stony Island was recommended by the Board for purchase through the Michigan Natural Resources Trust Fund in 1997. This purchase has now been finalized, thus ensuring the protection and preservation of this important piece of the Conservation Crescent.

Effectiveness and Further Steps

The next step in the process of the island's protection is the completion of a level one contamination study for remediation. This is being conducted through the Michigan Department of Natural Resources with the assistance of Grosse Ile Township. The contamination is primarily from fuel, machinery and equipment used during the dredging operations conducted on the island and is confined to the area where remaining buildings and sunken barges exist on the eastern side. Once clearly identified, remediation will take place.

The need to acquire land for the purpose of habitat protection and conservation in the Detroit River is very great. Yet, the means to achieve this goal is very difficult. Land acquired through conservation easements or donations is desirable, but the reality is that landowners prefer to develop these areas for profit. Acquiring Stony Island for preservation and protection through the Natural Resources Trust Fund is remarkable. It took vision, persistence and connections to make it happen. With a continued effort by many dedicated individuals, organizations, and groups, the goal of increasing the fish and wildlife habitat in the Detroit River can be realized.

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